None.
1. Field of the Invention
This invention is related to the preparation of aqueous dispersions of polymer blends. The polymer blends are composed of polycarboxypolyamide resins and alkali dispersible resins. The invention is further related to coatings, such as inks, floor finishes, paints, overprint varnishes, sizings, adhesives and the like employing the dispersions of the polymer blends.
2. Related Background Art
The preparation and use of alkali soluble resins are is closed in U.S. Pat. No. 5,183,847. These resins are carboxylated polyamide/acrylic resins and are synthesized in a two step fusion process. The polyamide is first condensed with a carboxylated rosin (e.g., maleated or fumarated rosin) at elevated temperatures in the range 200xc2x0-240xc2x0 C. and this fusion product is further condensed with an acrylic or styrene/acrylic copolymer at 230xc2x0 C. The resulting fusion resin can be dissolved or dispersed in water by neutralizing the acid groups with ammonia and/or amines.
In U.S. Pat. No. 5,180,782 compositions and methods of producing ammoniated water-soluble resins such as carboxylated polyamide-acrylic, carboxylated polyamide-styrene-acrylic or carboxylated polyamide-styrene-maleic resins are disclosed. The carboxylated polyamide is first prepared by the well-known procedure of heat fusion of a carboxylate rosin with a polyamide resin. The carboxylated polyamides resin must have an acid number of 65 or higher. The polyamide-acrylic resin is then prepared by blending, preferably at a temperature of 60 to 80xc2x0 C., an aqueous solution of the carboxylated polyamide fusion product with an ammoniated aqueous solution of styrene-acrylic, styrene-maleic or all-acrylic resin until the two resins are compatible. Also described are resins synthesized with acid numbers in the range of 80-150 by a high temperature (180-250xc2x0 C.) fusion reaction.
The use of anionic polyamide resin suspensoids in the preparation of paper products is disclosed in U.S. Pat. No. 2,926,117. The suspensoids employed are derived from polyamides prepared by reacting polymeric fatty acids with polyalkylene polyamines (e.g. diethylene triamine, triethylene tetraamine etc.). The polyamides are required to have high acid number of at least 50 and preferably 75-100. The polyamides are dispersed in an aqueous medium by reaction of the free carboxy groups with an aqueous alkali (e.g., inorganic and organic bases). The amount of alkali employed is only part of the quantity that would be required to completely neutralize the acid (usually, a quantity equivalent to an acid number of 25 to 50 is sufficient).
The dispersion process disclosed in U.S. Pat. No. 2,926,117 is carried out by mixing the resin with an aqueous alkali and heating the mixture. The resin disperses readily to form a stable suspensoid.
An example of a water dispersible polyamide blend is disclosed in U.S. Pat. No. 4,810,747. The polyamide blend is composed of two polyamide resins. The first resin comprises the reaction product of dibasic derivatives of fatty acids, monobasic acid and organic polyamides with an acid number of 20 to 50. The second resin comprises isophthalic acid, dibasic derivatives of fatty acids and organic polyamides with an acid number of 50 to 120. When the two resins are mixed the resulting polymer blend is water dispersible.
U.S. Pat. No. 4,973,617 disclose water-borne printing ink compositions based on acrylic resins and carboxylated rosin modified polyamides. The carboxylated rosin modified polyamides are prepared by a high temperature heat fusion process between a carboxylated rosin and polyamide polymer.
While many examples of aqueous resin blends containing polyamides modified by fusion reaction with a carboxylated resin are known, there remains a need for aqueous dispersions of polyamide resins that have relatively low acid number. Additionally, the polyamide resins should also be easily dispersed in basic aqueous solutions without large amounts of alcohol and have excellent storage stability.
This invention relates to polymer blends comprising a polycarboxypolyamide resin with an alkali dispersible resin. This invention also relates to the use of the polymer blends to prepare aqueous dispersions. The aqueous dispersions are generally comprised of 20 to 50 percent non-volatile material and 50 to 80 percent water. The aqueous dispersions are obtained by heating the polycarboxypolyamide resins with alkali dispersible resins in an aqueous medium. The dispersions have very fine particle size (i.e., less than 100 nm) and are useful as components of coatings (e.g., paints, varnishes, paper sizes, floor finishes, inks and adhesives, etc.).
In one preferred embodiment of the subject invention the polymer blend composition is useful in an aqueous dispersion and comprises: (a) a water insoluble polycarboxypolyamide resin in an amount from about 30 to about 90 percent by weight of the blend, having an acid number from about 25 to about 60; and (b) an alkali dispersible resin in an amount from about 10 to about 70 percent by weight of the blend. The polycarboxypolyamide resin has a number-average molecular weight of about 2,000 to about 20,000. Typically, the alkali dispersion resin has an acid number from about 75 to about 500 with a number-average molecular weight of about 500 to about 20,000.
The invention also relates to a blended polymer aqueous dispersion comprising:
(a) a water insouluble polycarboxypolyamide resin in an amount from about 30 to about 90 percent by weight of the total solids of the dispersion, having an acid number from about 25 to about 60;
(b) an alkali dispersible resin in an amount from about 10 to about 70 percent by weight of the total solids of the dispersion;
(c) at least one nonionic or anionic surfactant in an amount from about 0 to about 10 percent by weight of the total solids of the dispersion;
(d) a base in an amount from about 70 to about 150 percent of the amount required to neutralize acid functionality of the components (a) and (b); and
(e) water.
This invention also relates to methods for preparing aqueous dispersions of the disclosed polymer blends. Yet another embodiment of this invention is directed to coating compositions containing the aqueous dispersions disclosed in the subject application. These compositions include, for example, paper sizing agents, thermoset coatings, latexes and emulsion polymers, floor finishes, inks, adhesives and overprint varnishes. Another embodiment of this invention includes emulsion support resins prepared with the aqueous dispersions of this invention.
This invention relates to polymer blends of water insoluble polycarboxypolyamide resins which are readily dispersed in aqueous media in the presence of alkali dispersible resins. Additionally, the polymer blends may be comprised of nonionic or anionic surfactants.
Preferably, the polycarboxypolyamide resin comprises about 30 to about 90 percent of the total solids of the polymer blend composition. More preferably, the polycarboxypolyamide resin comprises about 50 to 80 percent of the total solids of the polymer blend.
The term xe2x80x9cpolycarboxypolyamide resinxe2x80x9d means polyamide resins containing carboxylic acid functionality. Typically, the polycarboxypolyamide resins are formed as the result of a high temperature fusion reaction between a polyamide resin and a carboxylic acid containing resin or as the result of a chemical condensation reaction between an excess of a carboxylic acid resin material (diacid) and an amine resin material (diamine).
The number-average molecular weight (Mn) of the polycarboxypolyamides generally range from about 2,000 to about 20,000. Preferably, the polycarboxypolyamides have acid numbers ranging from about 25 to about 60. More preferably, the polycarboxypolyamides have acid numbers ranging from about 35 to about 60. Most preferably, the polycarboxypolyamides have acid numbers ranging from about 45 to about 60.
The preparation of polycarboxypolyamides using condensation polymerization procedures for diacids and diamines is well-known in the art. The salt of the diamine and the diacid is formed when the diamine is added to molten diacid. At an elevated temperature (about 170-200xc2x0 C.), the salt eliminates water to form an amide bond. The desired acid number is achieved by adjusting the equivalents of diacid and diamine used in the condensation reaction.
Dimer acids or polymeric fatty acids are well-known in the art as the adducts of unsaturated C18-hydrocarbon acids. Typically, dimer acids are prepared from mixtures of oleic, linoleic, tall oil, or other fatty acids derived from vegetable and animal fats. Additionally, dimer acids are available commercially under a number of trademark names such as Empol(trademark) from Henkel Corporation, Emery Group of Cincinnati, Ohio; Sylvadym(trademark) from Arizona Chemical of Panama City, Fla.; Hystrenem from Humko, a division of Witco Corporation, of Memphis, Tenn.; and Unidyme(trademark) from Union Camp Corporation of Jacksonville, Fla. Typically, these dimer acids are comprised of a mixture of about 70 to 95 percent C36-diacid, 0 to 10 percent C18-monoacid and 0 to 25 percent C54-triacid.
In the subject invention dimer acids comprise about 50 to about 100 percent of the acid component of the polycarboxypolyamide. In one embodiment of the subject invention a dimer acid mixture with a higher fraction of trimer acid, e.g. Empol(trademark) 1040, may be used in place of the diacid to control the molecular weight of the resulting polycarboxypolyamide resin.
Other useful diacids of the present invention may have the following structure HOOCxe2x80x94Rxe2x80x94COOH and may be used to control the hydrophobicity and thermal properties of the polycarboxypolyamide resins, wherein R is alkylene, cycloalkylene or arylene. Examples of useful diacids are adipic acid, azelaic acid, suberic acid, sebacic acid, dodecanoic diacid, C21-diacid such as Westvaco(trademark) 1550 from Westvaco Chemicals of Charleston, S.C., terephthalic acid, isophthalic acid, phthalic acid and its anhydride, and cyclohexanedicarboxylic acids and anhydrides.
Triacids such as trimellitic anhydride and maleated or fumarated rosins may be used to modify the molecular weight and properties of the resulting polymers. Monofunctional acids such as propionic acid, stearic acid, oleic acid, tall oil fatty acid, benzoic acid, and rosin acids may be used to modify molecular weight or properties.
The diamines used in the preparation of the polycarboxypolyamide resins for the present invention may have the structure H2Nxe2x80x94Rxe2x80x94NH2, wherein R is alkylene, cycloalkylene or arylalkylene. Examples of appropriate diamines include but are not limited to the following, ethylene diamine, hexamethylene diamine, 2-methyl, 5-pentanediamine, m-xylylenediamine, 1,2-cyclohexanediamine and isophoronediamine. Diamines containing secondary amines can also be utilized, e.g., piperazine. Alkyl triamines such as diethylene triamine can be used to control the molecular weight of the resulting resins. Monofunctional amines such as cyclohexylamine and hexylamine may be used to control molecular weight or properties of the resulting resins. Low amounts of polyether diamines of the formula, H2Nxe2x80x94(RO)xxe2x80x94(Rxe2x80x2O)yxe2x80x94(RO)zxe2x80x94RNH2 may also be used, wherein R and Rxe2x80x2 are independently alkylene, cycloalkylene, or arylalkylene, x+y+z=1 to about 70 and x, y and z can vary independently between 0 and 70.
The alkali dispersible resins (ADRs) employed in this invention include alkali soluble resins. Preferably, the ADRs employed in the subject invention comprise about 10 to about 70 percent of the total solids of the polymer blend. More preferably, the ADRs comprise about 20 to about 50 percent of the total solids of the polymer blend. Preferably, the ADRs have a Mn about 500 to about 20,000, more preferably from about 500 to about 10,000, and most preferably from about 500 to about 7000. Preferably, the ADRs have an acid number of about 75 to about 500, more preferably from about 75 to about 300 and most preferably from about 100 to about 250.
Preferably, the ADRs contain an amount of aliphatic or cycloaliphatic moieties in addition to the acid bearing moieties. More preferably, the ADRs are dibasic acid (e.g., fumaric acid or maleic anhydride) modified rosin and derivatives thereof (esters, primarily), shellacs, and polymers of acid functional ethylenically unsaturated monomers and other ethylenically unsaturated monomers.
Most preferably, the ADRs are polymers of acrylic acid, methacrylic acid or maleic anhydride and other ethylenically unsaturated monomers.
Suitable acid-functional ethylenically unsaturated monomers include but are not limited to aconitic acid, acrylic acid, beta-carboxymethyl acrylate, cinnamic acid, crotonic acid, fumaric acid, itaconic acid, maleic acid, methacrylic acid, and mixtures thereof. Also suitable are certain monomers that are said to contain so-called xe2x80x9clatentxe2x80x9d acid moieties, such as cyclic anhydrides. Accordingly, suitable cyclic anhydrides include but are not limited to itaconic anhydrides, maleic anhydride, and mixtures thereof.
Suitable aromatic ethylenically unsaturated monomers include but are not limited to styrene, xcex1-methylstyrene, xcex2-methylstyrene, cis-stilbene, trans-stilbene, para-methylstyrene, tert-butylstyrene, vinylnapthalene, and various mixtures and combinations thereof.
Suitable non-aromatic ethylenically unsaturated monomers include but are not limited to xcex1-olefins; dienes; vinyl esters and ethers; C1 to C20 acrylate and methacrylate esters; acrylamides and methacrylamides; vinyl amides; and various mixtures and combinations thereof.
A preferred alkali soluble resin includes a polymer of acrylic acid and at least one ethylenically unsaturated monomer selected from styrene, alpha-methyl styrene and C1-C20 alkyl acrylates and methacrylates.
This invention also relates to a method to disperse the polymer blend comprising a polycarboxypolyamide and an ADR in water using a base. The amount of the base used in the dispersion ranges from about 70 to about 150 percent of the calculated amount needed to neutralize the acid functionality present in the polymer blend. The base may be selected from the group consisting of hydroxides of Group I elements such as sodium, potassium or lithium; ammonia; amines such as ethanol amine, diethanol amine, triethanol amine, diethylethanol amine; and volatile amines. Preferably the base is a volatile amine such as ammonia, methylamine, diethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, propylamine, isopropylamine, di-isopropylamine, dipropylamine, butylamine, sec-butylamine, tert-butylamine, 2-dimethylamino-2-methyl-1-propanol, dimethylethanol amine and various mixtures and combinations thereof. More preferably the base is ammonia.
The invention also relates to a method for preparing a blended polymer aqueous dispersion comprising the steps of:
(a) blending at a temperature from about 100xc2x0 C. to about 190xc2x0 C.;
(i) a water insoluble polycarboxypolyamide resin in an amount from about 30 to about 90 percent by weight of the total solids of the dispersion, having an acid number from about 25 to about 60; and
(ii) an alkali dispersible resin in an amount from about 10 to about 70 percent by weight of the total solids of the dispersion to form a polymer blend; and
(b) adding to said polymer blend:
(i) at least one nonionic or anionic surfactant in an amount from about 0 to about 10 percent by weight of the total solids of the dispersion;
(ii) a base in an amount from about 70 to about 150 percent of the amount required to neutralize acid functionality of the components (a)(i) and (a) (ii) to form a predispersion mixture; and
(iii) water; and
(c) mixing said predispersion mixture at a temperature from about 25xc2x0 C. to about 160xc2x0 C. to form the blended polymer dispersion.
In the method described above the polycarboxypolyamide resin and an alkali dispersible resin are heated at a temperature high enough to liquify the two polymers to form a polymer blend. Preferably, the polycarboxypolyamide and the ADR are heated at a temperature between 100xc2x0 C. and 190xc2x0 C. to form a polymer blend. More preferably, the polycarboxypolyamide and the ADR are heated at a temperature between 140xc2x0 C. and 190xc2x0 C. to form a polymer blend. Most preferably, the polycarboxypolyamide and the ADR are heated at a temperature between 140xc2x0 C. and 170xc2x0 C. to form a polymer blend. The resulting polymer blend is added to an ammoniated water solution either in the presence or absence of at least one nonionic or anionic surfactant in an amount from about 0 to about 10 percent by weight of the blend to form a predispersion mixture. Preferably, the predispersion mixture is mixed at a temperature between about 25xc2x0 C. and 160xc2x0 C. for about one to four hours. More preferably, the predispersion mixture is mixed at a temperature between about 60xc2x0 C. and 90xc2x0 C. for about one to four hours. Most preferably, the predispersion mixture is mixed at a temperature of about 85xc2x0 C. for about two hours.
The invention is also related to a method for preparing a blended polymer dispersion comprising the steps of:
(a) blending at a temperature from about 100xc2x0 C. to about 190xc2x0 C.;
(i) a water insoluble polycarboxypolyamide resin in an amount from about 30 to about 90 percent by weight of the total solids of the dispersion, having an acid number from about 25 to about 60;
(ii) an alkali dispersible resin in an amount from about 10 to about 70 percent by weight of the total solids of the dispersion; and
(iii) at least one nonionic or anionic surfactant in an amount from about 0 to about 10 percent by weight of the total solids of the dispersion to form a polymer blend; and
(b) adding to said polymer blend:
(i) a base in an amount from-about 70 to about 150 percent of the amount required to neutralize acid functionality of the components (a)(i) and (a)(ii) to form a predispersion mixture; and
(ii) water; and
(c) mixing said predispersion mixture at a temperature from about 25xc2x0 C. to about 160xc2x0 C. to form the blended polymer dispersion.
The invention is further related to a method for preparing a blended polymer dispersion comprising the step of: blending at a temperature from about 60xc2x0 C. to about 1600 C;
(i) a water insoluble polycarboxypolyamide resin in an amount from about 30 to about 90 percent by weight of the total solids of the dispersion, having an acid number from about 25 to about 60;
(ii) an alkali dispersible resin in an amount from about 10 to about 70 percent by weight of the total solids of the dispersion;
(iii) at least one nonionic or anionic surfactant in an amount from about 0 to about 10 percent by weight of the total solids of the dispersion;
(iv) a base in an amount from about 70 to about 150 percent of the amount required to neutralize acid functionality of the components (i) and (ii) to form the blended polymer dispersion; and
(v) optionally water.
In the method for the preparation of the blended polymer dispersion described above, wherein the components (i)-(v) are mixed, the resulting mixture is heated at a temperature of about 60xc2x0 C. to about 160xc2x0 C. for about 1 to about 4 hours to form the desired dispersion. The water (v) may be present while heating or added after the step of heating. In a preferred embodiment for the preparation of the blended polymer dispersion the mixture is heated at 85xc2x0 C. for about 2 hours to form the blended polymer dispersion.
In the methods disclosed herein the preparation of polymer blends may be carried out under an inert atmosphere. Suitable inert atmospheres include nitrogen or argon gases. If desired, preparation of the polymer blends may be conducted under pressure.
This invention is related to the preparation of industrially useful polycarboxypolyamide containing polymeric dispersions. The dispersions are prepared by mixing and heating two resins, that are compatible or partially compatible, in an aqueous medium. Typically, a polycarboxypolyamide resin with an acid number from about 25 to about 60 is mixed with an acrylic or carboxylated rosin ester resin having a higher acid number from about 75 to about 500 in the presence of an aqueous medium resulting in the formation of the dispersion. The dispersions have a high percentage of solids, excellent storage stability and may be formulated without environmentally harmful solvents. The stable dispersions have very fine particle size, e.g., less than 100 nm, and are useful as components of floor finishes, coatings, pigment dispersions, inks, paper sizing agents, adhesives, emulsion polymers and emulsion support resins.
Another embodiment of the invention is related to a water-based coating composition containing the above-described blended polymer aqueous dispersion and an emulsion polymer of at least one ethylenicallyunsaturated monomer, preferably at least two ethylenically unsaturated monomers selected from the group consisting of styrene, alpha-methyl styrene, C1-C20 alkyl acrylates and methacrylates and methacrylic acid. Particularly preferred ethylenically unsaturated monomers include styrene, butyl acrylate, alpha-methyl styrene, methylmethacrylate, methacrylic acid, butyl methacrylate, isobutyl methacrylate and 2-ethylhexyl acrylate. The preparation of such water-based coating compositions is well within the skill of those of ordinary skill in the art. Typical preparations of overprint varnishes, inks, coatings, floor finishes and adhesives are described below.
Overprint varnishes of this invention may be prepared using the aqueous dispersions of this invention and at least one emulsion polymer. Low molecular weight dispersible resins may be added to enhance gloss and printing qualities. Coalescing solvents or plasticizers may be added, if needed. Other additives, such as surfactants, waxes and wax emulsion, crosslinkers such as ZnO or aziridines, and defoamers, can be added to improve properties. Water and/or water miscible solvents can be added to adjust the viscosity of the overprint varnish formula.
Inks of this invention may be prepared using the aqueous dispersions of this invention in combination with a pigment or pigment dispersion and at least one emulsion polymer. Aqueous pigment dispersions are commercially available or can be produced by dispersing pigments in aqueous solutions of surfactants and/or low molecular weight alkali soluble resins, and in the case of certain pigments, such as titanium dioxide, in aqueous emulsion polymers. Coalescing solvents or plasticizers may be added, if needed. Other additives, such as surfactants, waxes and wax emulsions, crosslinkers such as ZnO or aziridines, and defoamers, can be added. Water and/or water miscible solvents can be added to adjust the viscosity of the ink formula.
Coatings of this invention may be prepared in a manner very similar to inks. In some coating compositions, like wood coatings, no pigment is needed. Coalescing solvents or plasticizers may be added, if needed. Other additives, such as surfactants, waxes and wax emulsions, flow additives, thickeners, and defoamers, can be added. Water and/or water miscible solvents can be added to adjust the viscosity of the coating formula.
Adhesives of this invention may be prepared in a method similar to overprint varnishes. Adhesives include at least one emulsion polymer. Coalescing solvents or plasticizers may be added, if needed. Other additives, such as tackifiers, surfactants, waxes and wax emulsions, flow additives, thickeners, crosslinkers such as ZnO or aziridines, and defoamers, can be added to improve properties. Water and/or miscible solvents can be added to adjust the viscosity of the adhesive formula. See e.g., U.S. Pat. No. 5,349,009 and U.S. Pat. No. 5,439,960.
The invention also includes sizing agent compositions comprised of the blended polymer aqueous dispersion and starch. Amounts of blended polymer aqueous dispersion and starch are admixed to provide the desired sizing properties. Such amounts can be readily determined by one skilled in the art without undue experimentation.
The thermoset coating compositions of this invention include the blended polymer aqueous dispersion in combination with a crosslinking agent in an amount effective to provide the desired degree of crosslinking. Exemplary crosslinkers include melamine based crosslinkers and derivatives thereof which are readily available.
The invention is also directed to resin supported emulsion polymers prepared with the aqueous dispersions of this invention. A resin supported emulsion polymer may be prepared by polymerizing ethylenically unsaturated monomers in the presence of the water dispersible polymers of this invention. Exemplary ethylenically unsaturated monomers have been described previously herein. Water, at least one dispersion of a low molecular weight water dispersible polymer, and, optionally, at least one surfactant is added to a flask equipped with stirring means, a thermometer, and a condenser. This mixture is heated to the desired temperature under a low flow of dry nitrogen. A monomer mixture is prepared. An initiator, usually a persulfate salt, solution is prepared by dissolving the initiator in water.
At this point, a precharge of the monomer may be added, if desired. After a suitable hold period, the initiator solution is added to the hot aqueous resin mixture. The monomer is added dropwise to the hot aqueous resin mixture over a period of time required to maintain a good balance between monomer concentration and rate of polymerization. More initiator solution may be added at the end of the monomer addition, if desired. The reaction mixture is then held at the reaction temperature for a period of time to reduce the monomer concentration. The emulsion polymer is then cooled and filtered.
A particular preferred coating of this invention is a floor finish composition. A commercial floor finish requires a polymer to produce a film which protects the floor material it is applied to from deterioration. Such deterioration may result from scuffing, scratching, and black marking caused by people traffic, i.e., soles and heels of shoes, as well as wheeled vehicles, e.g., shopping carts, baby strollers, stocking carts, dollies, hand trucks and the like. In addition to flooring protection, a high gloss appearance is also mandatory for a floor finish product. In general, the two most important requirements of a floor finish composition are to impart gloss as well as resistance to scuffing and black heel marking to the coated flooring. It has been found that floor finish compositions of this invention meet those requirements.
The polymer components of the floor finishes of this invention result in a well coalesced film to achieve high gloss and resistance to scuffing and black heel marking. Besides the blended polycarboxypolyamide/alkali dispersible resin polymer aqueous dispersion of this invention, the floor finish compositions of this invention also include an emulsion polymer, a wax or wax dispersion, at least one coalescing aid and water.
If desired, an ionic crosslinking agent may also be employed as part of the floor finish composition to further enhance film durability. Usually, a general requirement of a floor finish composition is that the finish coating be easily and completely removed from the flooring material when desired. Non-permanent floor finishes are removable with commercial strippers composed of alkali and organic solvents. Since removability is generally desirable, ionic crosslinkers are preferred over organic crosslinkers since ionic crosslinking is reversible when floor finish coating compositions are subjected to commercial strippers.
The emulsion polymer employed in the floor finish composition of this invention is generally a styrene/acrylic or acrylic copolymer having a glass transition temperature (Tg) of greater than 50xc2x0 C. (Jordan), preferably between about 50xc2x0 C. to about 100xc2x0 C., and most preferably about 65xc2x0 C. to 95xc2x0 C. The Tg of the styrene/acrylic or acrylic floor finish polymer effects the scuff and black heel mark resistance of the polymer film. Generally, styrene/acrylic or acrylic emulsion polymer having a relatively low Tg, e.g.  less than 50xc2x0 C. (Jordan), yield poorer scuff and black heel mark resistance properties than higher Tg analogs.
The emulsion polymer typically is prepared with an acid functional monomer, preferably methacrylic acid, in an amount between about 5 to about 30%, more preferably between about 15 to about 25% by weight of styrene/acrylic monomer. Generally, the amount of emulsion polymer admixed component to the blended polycarboxypolyamide/alkali dispersible resin polymer aqueous dispersion component, on a nonvolatile solids basis, of this invention is between about 5% to 95%, more preferably 40 to 95%, and most preferably 70 to 85% by weight of the total weight of the blended polycarboxypolyamide/alkali dispersible resin polymer aqueous dispersion and the emulsion polymer components.
The preparation of emulsion polymers is well known to those skilled in the art. Generally such emulsion polymers are prepared with ethylenically unsaturated monomers. Other components may include initiators, surfactants or emulsifying agents, amines (alkali), chain transer agents and multifunctional organic crosslinking agents.
Exemplary ethylen cally unsaturated monomers for preparing emulsion polymers in a latex system include alkenoic acids having 3 to 6 carbon atoms, such as acrylic acid, methacrylic acid, crotonic acid; alkenedioic acids, such as itaconic acid, maleic acid or fumaric acid or mixtures thereof. Additional exemplary ethylenically unsaturated monomers comprising monomeric units include but are not limited to xcex1-olefins; dienes; viny: esters and ethers; C1 to C20 acrylate and methacrylate esters; acrylamides and methacrylamides; vinyl amides; styrene, xcex1-methylstyrene, xcex2-methylstyrene, cis-stilbene, trans-stilbene, para-methylstyrene, tert-buzylstyrene, vinylnapthalene, and various mixtures and combinations thereof.
Exemplary multi-functional comonomers that may be employed in emulsion polymers are polyethylenically unsaturated comonomers and include lower alkenyl (C1 to C4) lower alkenoates, for example vinyl crotonate, allyl acrylate, allyl methacrylate; di-lower a kenyl (C1 to C4) alkanedioates, for example, divinyl adipate, diallyl adipate; di-lower akienyl (C1 to C4) benzenedicarboxyiates, for example, diallyl phthalate; lower alkenediol (C1 to C4) di- or tri-lower alkenoates, for example, ethylene glycol diacrylate, ethylene glycol dimethacrylate, butanediol diacrylate, butanediol dimethacrylate; lower (C1 to C4) alkylene bisacrylamides and lower alkylene (C1 to C4) bis-methacrylamides, for example, methylene bis-acrylamide; triallyl cyanurate; and the like. They are generally added to the emulsion polymers at a level of 0.5 to 5% (dry weight), preferably 1.0 to 1.5%
In addition, certain copolymerizable monomers which assist in the stability of the emulsion polymer, e.g., vinyl sulfonic acid and 2-acrylamido-2-methyl propane sulfonic acid may be employed as latex stabilizers.
Conventional batch, semi-batch or continuous emulsion polymerization techniques may be utilized to prepare emulsion polymers. Generally, the monomers are polymerized in an aqueous medium under pressures not exceeding 100 atmospheres in the presence of a catalyst or initiator.
Suitable as polymerization catalysts or initiators are the water-soluble free-radical-formers generally used in emulsion polymerization, such as hydrogen peroxide, sodium persulfate, potassium persulfate and ammonium persulfate, as well as tert-butyl hydroperoxide, in amounts of between 0.01 and 3% by weight, preferably 0.01 and 1% by weight based on the total amount of the emulsion. They can be used alone or together with reducing agents such as sodium formaldehyde-sulfoxylate, ferrous salts, sodium dithionite, sodium hydrogen sulfite, sodium sulfite, sodium thiosulfate, as redox catalysts in amounts of 0.01 to 3% by weight, preferably 0.01 to 1% by weight, based on the total amount of the emulsion. Such free-radical-formers can be charged in the aqueous emulsifier solution or be added during the polymerization in doses.
Emulsion polymerization is generally carried out at a pH of between 2 and 7, preferably between 3 and 5. In order to maintain the pH range, it may be useful to work in the presence of customary buffer systems, for example, in the presence of alkali metal acetates, alkali metal carbonates or alkali metal phosphates. Polymerization regulators, like mercaptans, aldehydes, chloroform, ethylene chloride and trichloroethylene, can also be added in some cases.
Emulsifying agents that may be employed include those generally used in emulsion polymerization, as well as optionally present-protective colloids. Preferred protective colloids, but not limited to, are alkali soluble or dispersible resins as described in U.S. Pat. No. 4,529,787. It is also possible to use emulsifiers alone or in mixture with protective colloids.
The emulsifiers can be anionic, cationic, nonionic surface-active compounds or mixtures thereof. Suitable anionic emulsifiers are, for example, alkyl sulfonates, alkylaryl sulfonates, alkyl sulfates, sulfates of hydroxyalkanols, alkyl and alkylaryl disulfonates, sulfonated fatty acids, sulfates and phosphates of polyethyoxylated alkanols and alkylphenols, as well as esters of sulfosuccinic acid. Suitable cationic emulsifiers are, for example, alkyl quaternary ammonium salts, and alkyl quaternary phosphonium salts. Examples of suitable non-ionic emulsifiers are the addition products of 5 to 50 mols of ethylene oxide adducted to straight-chained and branch-chained alkanols with 6 to 22 carbon atoms, or alkylphenols, or higher fatty acids, or higher fatty acid amides, or primary and secondary higher alkyl amines; as well as block copolymers of propylene oxide with ethylene oxide and mixtures thereof. When combinations of emulsifying agents are used, it is advantageous to use a relatively hydrophobic emulsifying agent in combination with a relatively hydrophilic agent. The amount of emulsifying agent is generally from about 1 to about 10, preferably about 2 to about 8, weight percent of the monomers used in the polymerization.
The emulsifier used in the polymerization can also be added, in its entirety, to the initial charge to the polymerization zone or a portion of the emulsifier, e.g., from 90 to 25 percent thereof, can be added continuously or intermittently during polymerization.
Besides the blended polycarboxypolyamide/alkali dispersible resin polymer aqueous dispersion of this invention and an emulsion polymer component, a floor finish composition may also include a wax or wax dispersion, at least one coalescing aid, an ionic crosslinker and water.
Coalescing aids employed in this invention are generally organic solvents. The preferred coalescing aids used in the floor.finish compositions of this invention are glycol ether solvents based on ethylene or propylene glycol. Exemplary glycol coalescing aids include diethylene glycol ethyl ether, diproplyene glycol methyl ether, diethylene glycol propyl ether, dipropylene glycol-n-butyl ether, dipropylene glycol dibenzoate, diethylene glycol dibenzoate, propylene glycol dibenzoate, polypropylene glycol dibenzoate and polyethylene glycol dibenzoate. Other exemplary coalescing aids include dibutyl phthalate, diethyl phthalate, butylbenzyl phthalate, N-methyl-2-pyrrolidone, isodecyl benzoate, tributoxy ethyl phosphate and dibutoxy ethoxy ethyl adipate.
The type and amount of coalescing aid(s) used in the floor finish compositions of this invention can readily be determined by one of ordinary skill in the floor finish art. Typically, the type and amount of coalescing aids will be dependent upon the Tg of the styrene/acrylic or acrylic emulsion polymer. For example, higher Tg polymers generally require higher levels of coalescing aids than lower Tg polymers to produce well coalesced films. Therefore, the amount of coalescing aids can be minimized by reducing the Tg of the styrene/acrylic or acrylic emulsion polymer or by blending polymers having different glass transitions temperatures to provide a more environmentally favorable composition. However, the reduction in Tg must be balanced against the poorer scuff and black heel mark resistance found in lower Tg styrene/acrylic or acrylic emulsion polymers. The floor finish compositions of this invention having a polycarboxypolyamide component have been found to have excellent resistance properties.
The waxes or mixtures of waxes which may be used include waxes of a vegetable, animal, synthetic, and/or mineral origin, or mixtures thereof, such as carnauba, candelilla, Fischer-Tropsch wax, microcrystalline wax, lanolin, cocoa butter, cottonseed, stearin, Japan wax, bayberry, myrtle, mace, palm kernel, beeswax spermaceti, Chinese insect, mutton tallow, polyethylene (oxidized or not and including emulsions), polypropylene, copolymers of ethylene and acrylic esters, waxes obtained by the hydrogenation of coconut oil or soybean oils, and the mineral waxes such as paraffin, ceresin, montan, ozokerite and the like. Care should be taken in selecting the wax if water clarity is desired.
Wax-soluble or dispersible resins or gums may be substituted for up to 50% of the wax, by weight. Natural or synthetic materials, including terpene-phenolic resins, heat processed (run) Congo, wood rosin, oxidized petroleum wax and the like, are also suitable. Preferred water soluble or dispersible resins are styrene/acrylic resins as described in U.S. Pat. No. 4,529,787. These materials enhance the gloss and leveling characteristics of floor finish compositions.
The compositions are adapted to form clear glossy coatings. However, if desired, a colored appearance may be obtained by the introduction of water-soluble or oil-soluble dyes in suitable proportions. Examples of suitable dyes which may be used include iron blues, phthalocyanine blues and greens, and organic maroons. The amount of dye may be varied widely, depending on the effect desired.
The floor finish compositions of this invention may also include plasticizers, wetting aids, defoamers and antifoams, leveling aids and ionic crosslinking agents, if desired.
Examples of plasticizers that are suitable at low levels include benzylbutyl phthalate, dibutyl phthalate, dimethyl phthalate, triphenyl phosphate, 2-ethylhexylbenzyl phthalate, butylcyclohexyl phthalate, mixed benzoic acid and fatty oil acid esters of pentaerythritol, poly(propylene adipate) dibenzoate, diethyleneglycol dibenzoate, caprolactam, tetrabutylthiodisuccinate, butylphthalylbutyl glycolate, acetyltributyl citrate, dibenzyl sebacate, tricresyl phosphate, ethyl toluenesulfonamide, the di-2-ethylhexyl ester of hexamethyleneglycol diphthalate, di(methylcyclohexyl)phthalate, tributoxyethyl phosphate and tributyl phosphate. The particular plasticizer and the amount thereof which may be employed is chosen in accordance with the demand for compatibility and efficiency in insuring optimum performance and finish clarity.
Examples of wetting and emulsifying agents which may be added in formulating the floor finish of this invention include alkali metal and amine salts of higher fatty acids having 12 to 18 carbon atoms, such as sodium, potassium, ammonium or morpholine oleate or ricinoleate, as well as the common nonionic surface active agents. Certain fluorocarbon surfactants, which are well known to those skilled in the art, also may be employed as wetting agents. The wetting agents may improve the spreading action of the floor finish.
The nonionic wetting and emulsifying agents include those prepared by the addition of ethylene oxide to compounds containing one or more active hydrogen atoms, such as alkyl phenols, fatty alcohols, fatty acids, fatty mercaptans, fatty amines, fatty amides and polyols. In many cases, the fatty radical is replaced by other types of hydrocarbon radicals in these starting materials. The polyols are often block polymers or copolymers of propylene oxide and/or butylene oxide, so the entire nonionic surface active agent in these cases may be regarded as a block polymer of ethylene oxide attached to the more hydrophobic block polymer or copolymer. More than one block of either type may be present.
Certain plasticizers, such as tributoxyethyl phosphate, may also serve as leveling aids if desired. Other leveling aids are well known to those skilled in the art.
If desired, an ionic crosslinking agent may be employed in the floor finish compositions of this invention. This ionic crosslinking agent may be a polyvalent metal complex containing a polyvalent metal moiety, an organic ligand moiety and, if the crosslinker is added as a chelate to the formulation in solubilized form, an alkaline moiety. The polyvalent metal ion may be that of beryllium, cadmium, copper, calcium, magnesium, zinc, zirconium, barium, aluminum, bismuth, antimony, lead, cobalt, iron, nickel or any other polyvalent metal which can be added to the composition by means of an oxide, hydroxide, or basic, acidic or neutral salt which has an appreciable solubility in water such as at least about 1% by weight therein. The alkaline moiety may be provided by ammonia or an amine. The organic ligand may be ammonia or an amine or an organic bidentate amino acid. The amino acid bidentate ligand may be an aliphatic amino acid, but may also be a hetrocylic amino acid.
Defoamers and antifoams are commonly used in the practice of floor finish formulating to reduce or eliminate foam marks in the dried finish film. As the formulating art is currently practiced, these are typically fatty acids or silicone polymer emulsions. Silicone emulsions are preferred for their greater efficiency and long-term activity.
Other formulation ingredients, such as perfumes or odor masking agents, dyes or colorants, bacterocides or bacteriostats may be included in the floor finish compositions of this invention, if desired.
This invention will be better understood from the Experimental Details which follow. However, one skilled in the art will readily appreciate that the specific methods and results discussed are merely illustrative of the invention and no limitation of the invention is implied.
In the various examples which follow, the molecular weight of each polymer was determined via gel permeation chromatography (xe2x80x9cGPCxe2x80x9d) techniques, using tetrahydrofuran (xe2x80x9cTHFxe2x80x9d) as eluent and poly(styrene) standards. The poly(styrene) standards thus utilized, which are presently available from Polymer Laboratories, Limited, of Church Stretton, Great Britain, are more particularly characterized as having number-average molecular weights of 2,250,000; 1,030,000; 570,000; 156,000; 66,000; 28,500; 9,200; 3,250; and 1,250.
Empol(trademark) 1016(200 parts), a diacid product of Henkel Corporation, Emery Group of Cincinnati, Ohio, a drop of phosphoric acid, and one drop of DC 200(trademark) silicone fluid (1,000 centistokes; 0.001 square meters per second), manufactured by Dow Corning Corporation of Midland, Mich., were charged to a 4-neck round bottom flask. The flask was equipped with an overhead stirrer, a thermometer, a nitrogen inlet and a distillation apparatus. The distillation apparatus consisted of a steam jacketed packed column (glass beads), a Dean-Stark trap, and a condenser. The contents of the flask were heated to 110xc2x0 C. under a nitrogen flow of 0.2 L/min. 2-Methyl-1,5-pentanediamine (31.73 parts), sold as DYTEK(trademark) A by E.I. du Pont de Nemours and Company of Wilmington, Del., was added slowly. The temperature was raised gradually over the period of 2 hours to 200xc2x0 C. which was maintained for two hours, while the water was removed by condensation in a Dean-Stark trap. The final remnants of water were removed under a light vacuum of 21 inches (533 mm) of Hg at 200xc2x0 C. for 1 hour. The final polymer was a yellow, water insoluble rubbery material with an acid number of about 40 and a Tg of about xe2x88x9210xc2x0 C. The number (Mn), weight (Mw) and z average molecular weight (Mz) were determined to be 4,200, 13,200, and 30,000, respectively.
100 parts of Empol(trademark) 1016, 29.95 parts of adipic acid, a drop of phosphoric acid, and a drop of DC 200(trademark) silicone fluid were charged to a 4-neck round bottom flask. The flask was equipped with an overhead stirrer, a thermometer, a nitrogen inlet and a distillation apparatus. The distillation apparatus consisted of a steam jacketed packed column (glass beads), a Dean-Stark trap, and a condenser. The contents of the flask were heated to 155xc2x0 C. under a 0.2 L/min. stream of dry nitrogen. Isophorone diamine (48.79 parts) was added dropwise to the hot acid solution. Evolution of water began before the end of the addition. At the end of the addition, the temperature was raised to 170xc2x0 C. where it was held for 20 minutes. At the end of this time, the temperature was raised 10xc2x0 C. and held for an additional 20 minutes. This stepwise temperature ramp was continued until 200xc2x0 C. was attained and maintained for two hours. During this time, the water of reaction was removed. The final remnants of water were removed under a light vacuum of 21 inches (533 mm) of Hg at 200xc2x0 C. for 1 hour. The molten resin was discharged from the flask onto an aluminum foil sheet. This resin was water insoluble and had an acid number around 60 with a glass transition temperature (midpoint) of 42xc2x0 C. Characteristic molecular weights of this resin were 2,500 (Mn), 4,500 (Mw), and 7,000 (Mz).
This polycarboxypolyamide was prepared in the same manner as Polycarboxypolyamide 2. The reaction mixture contained Empol(trademark) 1016 (86.38 parts), Empo(trademark) 1040 (367.68 parts), a polybasic fatty acid from Henkel Corporation, Emery Group of Cincinnati, Ohio, adipic acid (140.25 parts) and isophorone diamine (206.01 parts). This resin had an acid number around 80 with a glass transition temperature (midpoint) of 46xc2x0 C. Characteristic molecular weights of this resin were 2,800 (Mn), 6,400 (Mw), and 11,000 (Mz).
This polycarboxypolyamide was prepared in the same manner as Polycarboxypolyamide,2. The reaction mixture contained Empol(trademark) 1016 (200 parts), adipic acid (59.9 parts) and isophorone diamine (108.08 parts). This water insoluble resin had an acid number around 41 with a glass transition temperature (midpoint) of 56xc2x0 C. Characteristic molecular weights of this resin were 3,300 (Mn), 6,300 (Mw), and 9,500 (Mz).
This polycarboxypolyamide was prepared by the method described in U.S. Pat. No. 4,810,747, the disclosure of which is incorporated by reference herein. The reaction mixture contained Empol(trademark) 1016 (100 parts), Westvaco(trademark) 1550 (41.91 parts; a difunctional fatty acid product manufactured by Westvaco Chemicals division of Charleston, S.C.), isophthalic acid (62.63 parts), adipic acid (5.04 parts), xylylenediamine (14.74 parts), isophorone diamine (73.70 parts) and xylene (25 parts). This water insoluble resin had an acid number around 58 with a glass transition temperature (midpoint) of 84xc2x0 C. Characteristic molecular weights of this resin were 2,400 (Mn), 5,100 (Mw), and 10,300 (Mz).
The polycarboxypolyamide was prepared in the same manner as Polycarboxypolyamide 1. The reaction mixture contained Empol(trademark) 1016 (200 parts), propionic acid (14.4 parts), and DYTEK A(trademark) (51.5 parts). This water insoluble resin had an acid number around 2 with a glass transition temperature (midpoint) of about xe2x88x9210xc2x0 C. Characteristic molecular weights of this resin were 3,500 (Mn), 10,700 (Mw), and 22,000 (Mz).
Several additional polycarboxypolyamide resins were prepared in a manner similar to that previously described.
18% Adipic Acid
This water insoluble polycarboxypolyamide had an acid number of about 41.0, a Tg (midpoint) of 10xc2x0 C. and a Mw (theoretical) of about 8000.
54% Empol(trademark) 1016 (a polymerized fatty acid)
29.5% IPDA (Isophorone Diamine)
16.5% Adipic Acid
This water insoluble polycarboxypolyamide had an acid number of 42, a Tg (midpoint) of 52xc2x0 C. and a Mw (gel permeation chromatography) of about 5900.
84% Empol(trademark) 1018 (a polymerized fatty acid)
14% IPDA (Isophorone Diamine)
2% EDA (Ethylene Diamine)
This water insoluble polycarboxypolyamide had an acid number of 44, a Tg (midpoint) of 3xc2x0 C. and a Mw (gel permeation chromatography) of about 10,500.
81% Empolwm 1018 (a polymerized fatty acid)
19% IPDA (Isophorone Diamine)
This water insoluble polycarboxypolyamide had an acid number of 41, a Tg (midpoint) of 18xc2x0 C. and a Mw (gel permeation chromatography of about 11,700.
Resin A
Pentalyn(trademark) 261 was the trade name of a dibasic acid-modified rosin ester from Hercules Incorporated of Wilmington, Del. This resin had a reported acid number between 190 and 210. The resin had a glass transition temperature (Tg) of 115xc2x0 C. The number, weight and z average molecular weights were determined to be 780, 3,000, and 10,000 respectively. The molecular weight distribution was dimodal.
Resin B
A resin comprised of about 37 percent alpha-methyl styrene, 32 percent styrene, and 31 percent acrylic acid was prepared by methods described in U.S. Pat. No. 4,529,787, the disclosure of which is incorporated by reference herein. This resin had an acid number of about 205 and a Tg of about 115xc2x0 C. The number, weight and z average molecular weights were determined to be 3,100, 8,400 and 15,000, respectively.
Resin C
A resin comprised of about 38 percent alpha-methyl styrene, 37 percent styrene, and 25 percent acrylic acid was prepared by methods described in U.S. Pat. No. 4,529,787. This resin had an acid number of about 155 and a Tg of about 112xc2x0 C. The number, weight and z average molecular weights were determined to be 3,200, 9,200 and 17,100 respectively.
Resin D
A resin comprised of about 50 percent butyl methylacrylate, 25 percent styrene, and 25 percent acrylic acid was prepared by methods described in U.S. Pat. No. 4,529,787. This resin had an acid number of about 185 and a Tg of about 65xc2x0 C. The number, weight and z average molecular weights were determined to 3,400, 9,000 and 16,700, respectively.
Resin E
A resin comprised of about 34% alpha-methyl styrene, 33% acrylic acid and 33% styrene (by weight) was prepared by methods described in U.S. Pat. No. 4,529,787. This resin had an acid number of about 217 and a Tg of about 95xc2x0 C. The weight average molecular weight was about 5500.
Preparation of Dispersions